Who writes unit tests and isolated tests in your team?

In our team, unit tests are usually written by developers, as they best understand the internal logic of the code and can cover it most effectively. Isolated tests (mock tests, integration tests) are often written by QA Automation engineers, especially when testing interactions between components or external services.

This approach allows for a division of responsibility: developers ensure quality at the code level, while QA focuses on broader testing and automation.